If your microwave activates upon opening the door, this issue is most likely due to a malfunctioning door. Typically, the door latch contains a switch that operates the microwave, similar to how it controls the lighting. When this switch doesn't work properly, the microwave may either persist in running or cease running when the door is opened.

Your Microwave Has a Faulty Door

A malfunctioning door is the primary cause of microwave operational issues. Typically, a door is equipped with 2 or 3 interlock switches that ensure uninterrupted operation. These switches are responsible for the microwave's lights activating when the door is opened (source).

The interlock switch associated with the door latch serves the crucial role of allowing the microwave to run only when the door is securely closed. Meanwhile, metal prongs connected to the interlock switch detect the door's status, whether it's open or closed. These prongs prevent the microwave from operating when you press the button (in the case of an open door) by sending signals to the motor.

Therefore, it's vital to verify the proper functioning of the door latch because, in most instances, a faulty latch can complicate the operation of the interlock switches. A microwave with a defective door poses a significant risk of severe burn injuries to the user and can potentially harm other nearby electronic devices (source).

The Interlock Switches Stay Pressed

When you consider the situation, the fundamental problem behind a microwave running on its own is the interlock switches on the door getting stuck in the pressed position. Normally, these switches are designed to return to their initial position after being pressed. When they fail to do so, the microwave will continue to operate (source).

This particular problem is persistent, meaning that the microwave will continue functioning even after the door has been closed. If this is indeed the issue, your microwave will activate as soon as you press the power button.

Your Microwave Switches Are Heat-Sensitive

In certain cases, microwaves are equipped with heat-sensitive switches. These switches can be triggered even by the slightest heat, whether from your hands or other nearby sources if the door is faulty.

To determine if heat sensitivity is the problem, you can conduct an isolation test by separating your microwave from other devices. Then, try using a cold object, such as a pen, to operate the buttons. If the issue persists, it's likely related to a different problem. However, if the problem is resolved when using a cold object, then heat sensitivity is indeed the issue.

Pros and Cons Microwave


  • Speed
  • Convenience
  • Energy Efficiency
  • Preserves Nutrients
  • Even Heating


  • Limited Cooking Methods
  • Texture Changes
  • Uneven Heating
  • Limited Capacity
  • Safety Concerns

Differences Between Microwave and Dryer


Microwaves typically require minimal maintenance, such as cleaning the interior and exterior and replacing the occasional faulty component.


Dryers require more maintenance, including cleaning the lint filter after each use, checking and cleaning the vent system regularly, and servicing gas dryers as needed.

Alternative to Microwave

Conventional Oven

A conventional oven can be used to heat or cook food just like a microwave, although it takes longer to preheat and cook. It's ideal for baking, roasting, and broiling. Use oven-safe dishes and pans for this method.

How To Fix a Faulty Door

It's crucial to address the issue of a faulty microwave door to ensure it only operates when properly closed. You'll need specific tools such as a screwdriver and a replacement switch to perform this repair.

Before commencing the repair of the faulty door, it's essential to take safety precautions: make sure the microwave is unplugged, and the capacitor is not charged. Below are the steps I follow to repair a faulty door:

  1. Repair the Smartboard: Begin by removing the upper part of the microwave cabinet and then detach the keypad. Behind the keypad, you'll find the smartboard.
  2. Identify Interlock Switches: Determine how many interlock switches your microwave door has and locate their precise positions. You can also consult the microwave oven manual for information on the number and location of these switches.
  3. Access the Front Electric Panel: Carefully open the fasteners without causing any damage, and then open the electric panel.
  4. Remove the Switch Assembly: Once the electric panel is accessible, carefully remove the three or four switches from the board.
  5. Identify the Faulty Switch: When you press a switch on the microwave, it should return to its original position. Faulty switches are the ones that remain pressed and don't return. Test each switch to identify the faulty ones.
  6. Replace Faulty Switches: After pinpointing the faulty switches, obtain the exact replacement models, purchase them, and install them in place of the faulty switches.
  7. Reassemble All Components: Carefully reassemble all the parts in their original positions. Ensure everything is properly in place. After verifying the reassembly, plug in the microwave and check if it operates correctly, with the assurance that it no longer runs when the door is open if the repair was successful.

Should You Hire a Professional To Fix Your Microwave?

If you lack confidence in fixing your microwave or if it has more serious issues, it is strongly recommended that you hire a professional to assist with the repair.

Microwave repair can involve electrical components and safety precautions, and a professional technician will have the expertise and tools needed to diagnose and resolve complex problems safely.

Your safety and the proper functioning of your appliance are of utmost importance, so seeking professional help is a wise choice when in doubt or when dealing with significant microwave issues.


When a microwave continues running even with an open door, the root causes are often related to malfunctioning interlock switches and issues with the door latches. This problem may result from factors such as heat sensitivity or switches being stuck in the pressed position.

Repairing faulty microwave doors involves the replacement of these switches. However, it's essential to exercise caution when disassembling microwave components and accessing the smartboard. Ensure that no electricity is connected to the microwave during the repair to prioritize safety.

While it is possible to repair a faulty microwave door on your own, especially if you have experience repairing computer motherboards, it's important to note that professional assistance may be necessary in more complex cases or if you lack confidence in your skills.

The process of repairing a microwave door's smartboard can be similar to repairing a computer motherboard in terms of appearance and components. Still, it's crucial to assess the specific problem and your comfort level with the repair before deciding to proceed on your own.

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My name is Wisdom Bassey, I'm a blog content writer and graphic designer who provides support and services for brands and different companies. I'm young and versatile, A tech enthusiast. I carry out deep research on every topic I choose to write about. You can reach me through my social media handles, I'm always available and ready to connect.

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